ARM: dts: stm32: remove "@" and "_" from stm32f7 pinmux groups

Replace all "@" and "_" by "-" in pinmux groups for stm32f7 family.
This avoid errors when using yaml to check the bindings.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32f7-pinctrl.dtsi

@@ -127,7 +127,7 @@ gpiok: gpio@40022800 {
 				st,bank-name = "GPIOK";
 			};
 
-			cec_pins_a: cec@0 {
+			cec_pins_a: cec-0 {
 				pins {
 					pinmux = <STM32_PINMUX('A', 15, AF4)>; /* HDMI CEC */
 					slew-rate = <0>;
@@ -136,7 +136,7 @@ pins {
 				};
 			};
 
-			usart1_pins_a: usart1@0 {
+			usart1_pins_a: usart1-0 {
 				pins1 {
 					pinmux = <STM32_PINMUX('A', 9, AF7)>; /* USART1_TX */
 					bias-disable;
@@ -149,7 +149,7 @@ pins2 {
 				};
 			};
 
-			usart1_pins_b: usart1@1 {
+			usart1_pins_b: usart1-1 {
 				pins1 {
 					pinmux = <STM32_PINMUX('A', 9, AF7)>; /* USART1_TX */
 					bias-disable;
@@ -162,7 +162,7 @@ pins2 {
 				};
 			};
 
-			i2c1_pins_b: i2c1@0 {
+			i2c1_pins_b: i2c1-0 {
 				pins {
 					pinmux = <STM32_PINMUX('B', 9, AF4)>, /* I2C1 SDA */
 						 <STM32_PINMUX('B', 8, AF4)>; /* I2C1 SCL */
@@ -172,7 +172,7 @@ pins {
 				};
 			};
 
-			usbotg_hs_pins_a: usbotg-hs@0 {
+			usbotg_hs_pins_a: usbotg-hs-0 {
 				pins {
 					pinmux = <STM32_PINMUX('H', 4, AF10)>, /* OTG_HS_ULPI_NXT */
 						 <STM32_PINMUX('I', 11, AF10)>, /* OTG_HS_ULPI_DIR */
@@ -192,7 +192,7 @@ pins {
 				};
 			};
 
-			usbotg_hs_pins_b: usbotg-hs@1 {
+			usbotg_hs_pins_b: usbotg-hs-1 {
 				pins {
 					pinmux = <STM32_PINMUX('H', 4, AF10)>, /* OTG_HS_ULPI_NXT */
 						 <STM32_PINMUX('C', 2, AF10)>, /* OTG_HS_ULPI_DIR */
@@ -212,7 +212,7 @@ pins {
 				};
 			};
 
-			usbotg_fs_pins_a: usbotg-fs@0 {
+			usbotg_fs_pins_a: usbotg-fs-0 {
 				pins {
 					pinmux = <STM32_PINMUX('A', 10, AF10)>, /* OTG_FS_ID */
 						 <STM32_PINMUX('A', 11, AF10)>, /* OTG_FS_DM */
@@ -223,7 +223,7 @@ pins {
 				};
 			};
 
-			sdio_pins_a: sdio_pins_a@0 {
+			sdio_pins_a: sdio-pins-a-0 {
 				pins {
 					pinmux = <STM32_PINMUX('C', 8, AF12)>, /* SDMMC1 D0 */
 						 <STM32_PINMUX('C', 9, AF12)>, /* SDMMC1 D1 */
@@ -236,7 +236,7 @@ pins {
 				};
 			};
 
-			sdio_pins_od_a: sdio_pins_od_a@0 {
+			sdio_pins_od_a: sdio-pins-od-a-0 {
 				pins1 {
 					pinmux = <STM32_PINMUX('C', 8, AF12)>, /* SDMMC1 D0 */
 						 <STM32_PINMUX('C', 9, AF12)>, /* SDMMC1 D1 */
@@ -254,7 +254,7 @@ pins2 {
 				};
 			};
 
-			sdio_pins_b: sdio_pins_b@0 {
+			sdio_pins_b: sdio-pins-b-0 {
 				pins {
 					pinmux = <STM32_PINMUX('G', 9, AF11)>, /* SDMMC2 D0 */
 						 <STM32_PINMUX('G', 10, AF11)>, /* SDMMC2 D1 */
@@ -267,7 +267,7 @@ pins {
 				};
 			};
 
-			sdio_pins_od_b: sdio_pins_od_b@0 {
+			sdio_pins_od_b: sdio-pins-od-b-0 {
 				pins1 {
 					pinmux = <STM32_PINMUX('G', 9, AF11)>, /* SDMMC2 D0 */
 						 <STM32_PINMUX('G', 10, AF11)>, /* SDMMC2 D1 */